Systematic review on the biology, ecology, genetic diversity and parasite transmission potential of Panstrongylus geniculatus (Latreille 1811) in Latin America

Panstrongylus geniculatus (Latreille, 1811) is the triatomine with the largest geographic distribution in Latin America. It has been reported in 18 countries from southern Mexico to northern Argentina, including the Caribbean islands. Although most reports indicate that P. geniculatus has wild habitats, this species has intrusive habits regarding human dwellings mainly located in intermediate deforested areas. It is attracted by artificial light from urban and rural buildings, raising the risk of transmission of Trypanosoma cruzi. Despite the wide body of published information on P. geniculatus, many knowledge gaps exist about its biology and epidemiological potential. For this reason, we analysed the literature for P. geniculatus in Scopus, PubMed, Scielo, Google Scholar and the BibTriv3.0 databases to update existing knowledge and provide better information on its geographic distribution, life cycle, genetic diversity, evidence of intrusion and domiciliation, vector-related circulating discrete taxonomic units, possible role in oral T. cruzi transmission, and the effect of climate change on its biology and epidemiology.

Encuesta entomológica y caracterización de las viviendas con el vector de la enfermedad de Chagas, en aldea Chuchuapa, Santa Rosa, Guatemala / Entomological survey and characterization of houses with the vector of Chagas disease, in Chuchuapa village, Santa Rosa, Guatemala

En Guatemala en el 2015, el Ministerio de Salud Pública y Asistencia Social (MSPAS) reportó nuevos casos de la enfermedad de Chagas en la región suroriental del país, siendo Santa Rosa uno de los departamentos endémicos en donde Triatoma dimidiata es el principal transmisor. Se estimó la infestación de T. dimidiata en la aldea Chuchuapa, municipio de Santa María Ixhuatán, de abril a junio de 2019, se calcularon los índices en-tomológicos y se caracterizaron intra y peridomiciliar 149 viviendas (79.67% de las viviendas habitadas). Los datos se obtuvieron mediante un cuestionario mixto, en entrevista cara a cara y evaluación de las viviendas, por un equipo profesional experimentado, mediante el método y protocolo estándar hombre-hora. Se capturaron 20 triatominos en 10 viviendas, con un índice de infestación de 6.71% (10/149), un índice de densidad de 13.42% (20/149), 19 triatominos intradomiciliares y uno peridomiciliar, con un índice de infección natural por Tr y pano-soma cruzi intradomiciliar de 26.3% (5/19), índice de infección natural por T. cr u z i peridomiciliar de 100.0% (1/1) e índice de infección natural por T. c r u z i en los triatominos capturados de 30.0 % (6/20). Las viviendas infestadas presentaron techo de lámina, pared de bajareque con grietas y sin repello, piso de tierra y afiches en la pared, acumulación de leña u otros materiales tanto intra como peridomiciliar, convivencia con animales domésticos y tenencia de animales de corral. Los resultados representan un alto riesgo para la transmisión de la enfermedad de Chagas entre los habitantes de la aldea.

In Guatemala in 2015, the Ministry of Public Health and Social Assistance reported new cases of Chagas disease in the southeastern region of the country, with Santa Rosa being one of the endemic departments where Tr ia-toma dimidiata is the main transmitter. The infestation of T. dimidiata was estimated in the Chuchuapa village, municipality of Santa María Ixhuatán, from April to June 2019, the entomological indices were calculated and 149 dwellings were characterized intradomiciliary and peridomiciliary (79.67% of the inhabited dwellings). The data were obtained through a mixed questionnaire, in a face-to-face interview and evaluation of the dwellings, by an experienced professional team, using the standard man-hour method and protocol. 20 triatomines were captured in 10 homes, with an infestation index of 6.71% (10/149), a density index of 13.42% (20/149), 19 intradomiciliary triatomines and one peridomiciliary, with a natural infection index by intradomiciliary Trypanosomacruzi of 26.3% (5/19), natural infection index by peridomiciliary T. c r u z i of 100.0% (1/1) and natural infection index by T. c r u z i in captured triatomines of 30.0% (6/20). The infested dwellings have a sheet roof, awattle and daub wall with cracks and no wall plaster, dirt and posters on the wall, accumulation of firewood and other materials in both intradomiciliary and peridomiciliary, living with domestic animals and keeping poultry animals. The results represent a high risk for the transmission of Chagas disease among the villager.

Insect vectors of Chagas disease (Trypanosoma cruzi) in Northeastern Brazil

Abstract INTRODUCTION: Chagas disease remains a public health problem in the rural and urban areas of 19 countries in the Americas. METHODS: The aim of the present study was to investigate the Trypanosoma cruzi infection rate of triatomines collected from both intra- and peridomiciliary areas in eleven municipalities of Southeastern Ceará, Brazil, from 2009 to 2015. RESULTS: A total of 32,364 triatomine specimens, including nymphs and adults, were collected, and 31,736 (98.06%) of these were examined. More nymphs were collected than adults, and the greatest number of triatomines (n = 8,548) was collected in 2010, for which the infection rate was 1.3%, with the highest rate of infections observed for specimens from Quixere. The species collected during the study were identified as Triatoma pseudomaculata, Triatoma brasiliensis, Panstrongylus megistus, Panstrongylus lutzi, and Rhodnius nasutus, with T. pseudomaculata being the most abundant (n = 19,962). CONCLUSIONS: These results verify the presence of triatomines in both intra- and peridomiciliary areas, thereby ensuring persistence of the pathogen and consequently, the disease, as the presence of infected vectors in households is an important risk factor. According to these findings, the Chagas Disease Control Program should intensify its efforts in order to prevent the spread of the disease.

First report of Triatoma sordida Stål, 1859 (Hemiptera, Reduviidae, Triatominae) in the State of Acre and Brazilian Western Amazon

Abstract INTRODUCTION The occurrence of Triatoma sordida in the Brazilian Western Amazon is reported for the first time. METHODS Triatoma sordida specimens were collected from a Gallus gallus nest in a peridomiciliary area of Senador Guiomard municipality in the state of Acre. RESULTS The number of triatomine species in Acre increased from six to seven with this first report of T. sordida in the Brazilian Western Amazon. CONCLUSIONS The occurrence of T. sordida in Acre is of concern since it is among the most captured triatomines in peridomiciliary environments in Brazil, and carries a high potential for vector transmission.

Assessing the risk zones of Chagas' disease in Chile, in a world marked by global climatic change

BACKGROUND Vector transmission of Trypanosoma cruzi appears to be interrupted in Chile; however, data show increasing incidence of Chagas' disease, raising concerns that there may be a reemerging problem. OBJECTIVE To estimate the actual risk in a changing world it is necessary to consider the historical vector distribution and correlate this distribution with the presence of cases and climate change. METHODS Potential distribution models of Triatoma infestans and Chagas disease were performed using Maxent, a machine-learning method. FINDINGS Climate change appears to play a major role in the reemergence of Chagas' disease and T. infestans in Chile. The distribution of both T. infestans and Chagas' disease correlated with maximum temperature, and the precipitation during the driest month. The overlap of Chagas' disease and T. infestans distribution areas was high. The distribution of T. infestans, under two global change scenarios, showed a minimal reduction tendency in suitable areas. MAIN CONCLUSION The impact of temperature and precipitation on the distribution of T. infestans, as shown by the models, indicates the need for aggressive control efforts; the current control measures, including T. infestans control campaigns, should be maintained with the same intensity as they have at present, avoiding sylvatic foci, intrusions, and recolonisation of human dwellings.

Investigação de surto de doença de Chagas aguda na região extra-amazônica, Rio Grande do Norte, Brasil, 2016 / Investigation of an outbreak of acute Chagas disease outside the Amazon Region, in Rio Grande do Norte State, Brazil, 2016 / Investigación del brote de la enfermedad de Chagas aguda en la región extra-amazónica, Rio Grande do Norte, Brasil, 2016

Resumo: O objetivo do artigo foi confirmar e descrever um surto da doença de Chagas aguda por transmissão oral na mesorregião Oeste Potiguar, Rio Grande do Norte, Brasil. Trata-se de um estudo descritivo do tipo série de casos, tendo como fonte de dados os registros de atendimentos médicos e entrevistas com os casos suspeitos entre 16 de setembro e 19 de novembro de 2015. Realizou-se pesquisa entomológica nas prováveis localidades de infecção dos casos de doença de Chagas aguda. Foram confirmados 18 casos de doença de Chagas aguda em residentes de quatro municípios do Rio Grande do Norte. Os sinais e sintomas mais relatados foram febre e fraqueza (n = 18), seguidos de mialgia (n = 17), prostração, inapetência e edema de membros inferiores (n = 15). A mediana de duração da febre foi de 20 dias (intervalo: 6 a 45 dias). Quinze casos foram confirmados por critério laboratorial e três por vínculo epidemiológico com clínica compatível. Todos os casos confirmados relataram ter consumido caldo de cana da mesma procedência. Foram capturados 110 triatomíneos na fazenda onde ocorreu a moagem da cana consumida. Os insetos estavam no peridomicílio, em amontoados de lenha e próximos ao engenho. A maioria dos exemplares capturados era da espécie Triatoma brasiliensis, e apresentou um índice de infecção natural de 63%. Foi confirmado surto da doença de Chagas de transmissão oral por ingestão de caldo de cana contaminado por triatomíneo infectado, evidenciado pelo vínculo epidemiológico entre os casos investigados e a pesquisa entomológica no local provável de infecção.

Abstract: The aim of this article was to confirm and describe an outbreak of acute Chagas disease involving oral transmission in the western region of Rio Grande do Norte State, Brazil. This was a descriptive case series study in which the data sources were medical records and interviews with suspected cases from September 16 to November 19, 2015. An entomological investigation was conducted in the probable sites of infection for acute Chagas disease cases. Eighteen cases of acute Chagas disease were confirmed in residents of four municipalities (counties) in Rio Grande do Norte State. The most frequently reported signs and symptoms were fever and weakness (n = 18), followed by myalgia (n = 17), prostration, loss of appetite, and edema of the lower limbs (n = 15). Median duration of fever was 20 days (range: 6 to 45 days). Fifteen cases were confirmed by the laboratory criterion and three by epidemiological link with consistent clinical characteristics. All confirmed cases reported having consumed sugar cane juice from the same mill. A total of 110 triatomines were captured on the plantation where the sugar cane had been crushed for juice. The insects were found in the peridomicile, in stacks of firewood and close to the sugar cane mill. The majority of the captured specimens were Triatoma brasiliensis and showed a natural infection rate of 63%. The Chagas disease outbreak was confirmed with oral transmission via ingestion of sugar cane juice contaminated with infected triatomines, as evidenced by the epidemiological link between the investigated cases and the entomological survey in the probable site where the infection occurred.

Resumen: El objetivo de este artículo fue confirmar y describir un brote de la enfermedad de Chagas aguda por transmisión oral en la mesorregión oeste de Rio Grande do Norte, Brasil. Se trata de un estudio descriptivo del tipo serie de casos, contando como fuente de datos los registros de atención médica y entrevistas en los casos sospechosos entre el 16 de septiembre y el 19 de noviembre de 2015. Se realizó una investigación entomológica en las probables localidades de infección de los casos de enfermedad de Chagas aguda. Fueron confirmados 18 casos de enfermedad de Chagas aguda en residentes de cuatro municipios de Rio Grande do Norte. Los signos y síntomas más informados fueron fiebre y debilidad (n = 18), seguidos de mialgia (n = 17), postración, inapetencia y edema de miembros inferiores (n = 15). La media de duración de la fiebre fue de 20 días (intervalo: 6 a 45 días). Quince casos fueron confirmados por criterio de laboratorio y tres por vínculo epidemiológico con clínica compatible. Todos los casos confirmados informaron haber consumido caldo de caña de la misma procedencia. Fueron capturados 110 triatominos en la hacienda donde se produjo la molienda de la caña consumida. Los insectos estaban en el peridomicilio, en montones de leña y cerca del ingenio azucarero. La mayoría de los ejemplares capturados era de la especie Triatoma brasiliensis, y presentó un índice de infección natural de un 63%. Se confirmó un brote de la enfermedad de Chagas de transmisión oral por ingestión de caldo de caña contaminado por triatomino infectado, evidenciado por el vínculo epidemiológico entre los casos investigados y la investigación entomológica en el lugar probable de infección.

The eco-epidemiology of Triatoma infestans in the temperate Monte Desert ecoregion of mid-western Argentina

BACKGROUND The eco-epidemiological status of Chagas disease in the Monte Desert ecoregion of western Argentina is largely unknown. We investigated the environmental and socio-demographic determinants of house infestation with Triatoma infestans, bug abundance, vector infection with Trypanosoma cruzi and host-feeding sources in a well-defined rural area of Lavalle Department in the Mendoza province. METHODS Technical personnel inspected 198 houses for evidence of infestation with T. infestans, and the 76 houses included in the current study were re-inspected. In parallel with the vector survey, an environmental and socio-demographic survey was also conducted. Univariate risk factor analysis for domiciliary infestation was carried out using Firth penalised logistic regression. We fitted generalised linear models for house infestation and bug abundance. Blood meals were tested with a direct ELISA assay, and T. cruzi infection was determined using a hot-start polymerase chain reaction (PCR) targeting the kinetoplast minicircle (kDNA-PCR). FINDINGS The households studied included an aged population living in precarious houses whose main economic activities included goat husbandry. T. infestans was found in 21.2% of 198 houses and in 55.3% of the 76 re-inspected houses. Peridomestic habitats exhibited higher infestation rates and bug abundances than did domiciles, and goat corrals showed high levels of infestation. The main host-feeding sources were goats. Vector infection was present in 10.2% of domiciles and 3.2% of peridomiciles. Generalised linear models showed that peridomestic infestation was positively and significantly associated with the presence of mud walls and the abundance of chickens and goats, and bug abundance increased with the number of all hosts except rabbits. MAIN CONCLUSIONS We highlight the relative importance of specific peridomestic structures (i.e., goat corrals and chicken coops) associated with construction materials and host abundance as sources of persistent bug infestation driving domestic colonisation. Environmental management strategies framed in a community-based programme combined with improved insecticide spraying and sustained vector surveillance are needed to effectively suppress local T. infestans populations.

Análisis espacio-temporal de las condiciones biofísicas y ecológicasde Triatoma dimidiata (Hemiptera: Reduviidae: Triatominae)en la region nororiental de los Andes de Colombia / Spatio-temporal analysis of the biophysical and ecological conditions of Triatoma dimidiata(Hemiptera: Reduviidae: Triatominae) in the northeast region of Colombia

Resumen Introducción. Ante el desconocimiento del contexto espacio-temporal de las condiciones biofísicas (hidrometereológicas y de densidad de la cobertura vegetal) de las zonas con presencia deTriatoma dimidiata en Santander y Boyacá, es necesario dilucidar los patrones asociados con estas variables para determinar su distribución y control. Objetivo. Hacer el análisis espacio-temporal de las variables biofísicas relacionadas con la distribución de Triatoma dimidiata de los departamentos de Santander y Boyacá en la región nororiental de Colombia. Materiales y métodos. Se utilizaron las bases de datos de los registros de presencia de T. dimidiata y de factores hidrometereológicos del Special Report on Emissions Scenarios (SrES) del Intergovernmental Panel on Climate Change, IPCC. Se estudiaron las variables de temperatura, humedad relativa, pluviosidad y densidad de la cobertura vegetal a nivel regional y local, se hizo el análisis espacial y el geoestadfstico, asf como el análisis estadfstico descriptivo y temporal de las series de Fourier. Resultados. En las áreas con mayor presencia de T. dimidiata, las temperaturas a dos metros del suelo y en suelo cubierto oscilaron entre 14,5 y 18,8 °C, y la temperatura ambiente fue de 30 a 32 °C. La densidad de la cobertura vegetal y la pluviosidad en las áreas de mayor presencia de T. dimidiata exhibieron patrones de picos anuales y bienales. Los valores de la humedad relativa fluctuaron entre 66,8 y 85,1 %. Conclusiones. Las temperaturas a nivel de superficie y a dos metros del suelo fueron las variables determinantes de la distribución espacio-temporal de T. dimidiata. La elevada humedad relativa incentivó la búsqueda de refugios e incrementó la distribución geográfica en los picos anual y bienal de pluviosidad a nivel regional. Las condiciones ecológicas y antrópicas sugieren que T. dimidiata es una especie de gran resiliencia.

Abstract Introduction: Due to the lack of information regarding biophysical and spatio-temporal conditions (hydrometheorologic and vegetal coverage density) in areas with Triatoma dimidiata in the Colombian departments of Santander and Boyacá, there is a need to elucidate the association patterns of these variables to determine the distribution and control of this species. Objective: To make a spatio-temporal analysis of biophysical variables related to the distribution of T. dimidiate observed in the northeast region of Colombia. Materials and methods: We used the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) data bases registering vector presence and hydrometheorologic data. We studied the variables of environmental temperature, relative humidity, rainfall and vegetal coverage density at regional and local levels, and we conducted spatial geostatistic, descriptive statistical and Fourier temporal series analyses. Results: Temperatures two meters above the ground and on covered surface ranged from 14,5°C to 18,8°C in the areas with the higher density of T. dimidiata. The environmental temperature fluctuated between 30 and 32°C. Vegetal coverage density and rainfall showed patterns of annual and biannual peaks. Relative humidity values fluctuated from 66,8 to 85,1%. Conclusions: Surface temperature and soil coverage were the variables that better explained the life cycle of T. dimidiata in the area. High relative humidity promoted the seek of shelters and an increase of the geographic distribution in the annual and biannual peaks of regional rainfall. The ecologic and anthropic conditions suggest that T. dimidiata is a highly resilient species.

Triatoma dimidiata en Colombia; distribución, ecología e importancia epidemiológica / Triatoma dimidiata in Colombia: Distribution, ecology and epidemiological importance

RESUMEN Triatoma dimidiata es un importante vector de la enfermedad de Chagas en Centroamérica y en los países del norte de Suramérica. En Colombia, tiene una amplia distribución y su presencia se ha reportado en 14 departamentos de las regiones Andina, Caribe, de los Llanos Orientales y del Alto Magdalena, en las cuales ocupa diferentes ecótopos naturales y artificiales. La especie está clasificada como secundaria para la transmisión de Trypanosoma cruzi; sin embargo, su presencia en el ambiente silvestre, peridoméstico y doméstico en la región Andina, y su capacidad de movilizarse entre ellos, le han permitido escapar al control basado en la aspersión con piretroides y ello resalta su importancia en el mantenimiento de la transmisión del parásito debido a la potencial reinfestación de las viviendas. La comprensión de las relaciones de T. dimidiata con su hábitat, así como el empoderamiento de la comunidad, contribuyen al desarrollo de sistemas de control efectivos y perdurables. El propósito de esta revisión fue describir la distribución, los factores de riesgo, la ecología, las características entomológicas y los hábitats de las poblaciones de T. dimidiata en Colombia, y proponer alternativas de intervención acordes con las características particulares de esta especie.

ABSTRACT Triatoma dimidiata is an important vector of Chagas disease in Central America and countries of northern South America. In Colombia, it has a wide geographical distribution with reported presence in 14 departments in the Andean, Caribbean, Eastern plains and Upper Magdalena regions, where it occupies different natural and artificial ecotopes. The species is considered a secondary vector in the transmission of Trypanosoma cruzi. Its presence in wild, peridomestic and intradomiciliary habitats in the Andean region, coupled with its ability to move between them, has allowed it to escape the control based on pyrethroids spraying, highlighting its importance in maintaining transmission of the parasite through the potential reinfestation of homes. Understanding the relation of T. dimidiata and its habitats, as well as the empowerment of communities, will contribute to the development of effective and lasting control systems. The purpose of this review was to describe the distribution, risk factors, ecology, entomological features and habitats of T. dimidiata populations in Colombia, and to propose alternative interventions in agreement with the specific characteristics of the species.

¿Qué dicen los números de la evolución temporal de la enfermedad de Chagas? / What do the numbers tell us about the temporal evolution of Chagas’ disease?

Chagas disease remains highly prevalent in Chile, especially between the regions of Arica and Parinacota, and Coquimbo. Since 1999 it is considered that in Chile the vector transmission was interrupted. Under this premise, the epidemiological dynamics should be changing. We analyzed the evolution of the prevalence of Chagas’ disease analyzing 64,995 xenodiagnosis performed in the laboratory of Parasitology of the Faculty of Medicine of the University of Chile between 1949 and 2014. The evolution of the mortalities and incidences from the databases of the Ministry of Health in the periods in which it was analyzed. The rates of domiciliary infestation and the number of vector insects sent to the Public Health Institute and its trypano-triatomine indices were also analyzed. The prevalence of Chagas’ disease in inhabitants of risk areas remained stable in this period as well as mortality. The incidence rate shows a progressive increase with a tendency towards stabilization. A significant decrease in sampling effort was found, declining by two orders of magnitude, especially since 2000. The progressive increase in morbidity had no clear relation to the interruption of the vector chain nor to the greater diagnostic effort occurred in 2009, since it was evident from before. While home infestation declines, reports of intrusion of solitary individuals and wild foci of T. infestans have increased. Trypano-triatomine indices were maintained with high values in all vector species. This study shows a worrying situation, for while on the one hand the interruption of the vector transmission and improvement in the research systems is emphasized, the concern for this disease seems to be decreasing with less diagnostic efforts and lower education at the higher level, and by the other hand the numbers show that the problem if it is not increasing, at least maintains its careless historical magnitude.

Resumen Introducción: La enfermedad de Chagas sigue siendo altamente prevalente en Chile, especialmente entre las regiones de Arica y Parinacota y de Coquimbo. Desde 1999 se considera que en Chile se encuentra interrumpida la transmisión vectorial. Bajo esta premisa, la dinámica epidemiológica se debiera estar modificando. Objetivo: Analizar la evolución temporal de la enfermedad de Chagas en Chile Material y Métodos: Analizamos la evolución de la prevalencia de la enfermedad de Chagas a través del análisis de resultados de 64.995 xenodiagnós-ticos realizados en el laboratorio de Parasitología de la Facultad de Medicina de la Universidad de Chile, entre 1949 y 2014. Se estudió la evolución de las mortalidades e incidencias disponibles en las bases de datos del Ministerio de Salud en los períodos en que fue posible. Se analizaron las tasas de infestación domiciliaria y el número de insectos vectores enviados al Instituto de Salud Pública y sus índices tripano-tratominos. Resultados: La prevalencia de la enfermedad de Chagas en habitantes de zonas de riesgo se mantuvo estable en este período, al igual que la mortalidad. La tasa de incidencia muestra un incremento progresivo con tendencia a la estabilización. Se encontró un significativo decrecimiento del esfuerzo de muestreo, decayendo dos órdenes de magnitud, especialmente desde 2000. El aumento progresivo de la morbilidad no tiene clara relación con el corte de la cadena vectorial ni con el mayor esfuerzo diagnóstico ocurrido en 2009, ya que era evidente desde antes. Mientras que la infestación domiciliaria disminuye, han aumentado los reportes de intromisión de individuos solitarios y los focos silvestres de T. infestans. Los índices tripano triatominos se mantienen con valores altos en todas las especies vectores. Discusión: Este estudio muestra una situación preocupante, ya que mientras por una parte se destaca el corte de la transmisión vectorial y mejora en los sistemas de pesquisa, la preocupación por esta enfermedad parece ir decreciendo con menores esfuerzos diagnósticos y menor enseñanza a nivel superior, y por otra parte los números muestran que el problema si es que no está aumentando, al menos mantiene su descuidada magnitud histórica.

First report of Sapajus cay naturally infected by Trypanosoma cruzi in San Pedro Department, Paraguay / Primeiro relato de infecção natural em Sapajus cay por Trypanosoma cruzi em Departamento San Pedro, Paraguai

Abstract To verify the occurrence of natural Trypanosoma cruzi infection in non-human primates from a rural endemic area of the east region of Paraguay, xenodiagnosis was performed in 35 animals belonging to two species. For genotyping and T. cruzi discrete typing unit (DTU) assignment, a combination of four markers was used, including amplification products of the small (18S) and large (24Sα) subunits of ribosomal ribonucleic acid gene, the intergenic region of mini-exon gene and the heat shock protein 60 Eco-RV polymerase chain reaction-restriction fragment length polymorphism (HSP60/EcoRV-PCR-RFLP). One specimen of Sapajus cay was found positive and infected by the DTU TcII. This result constitutes the first record of natural T. cruzi infection in a sylvatic monkey in Paraguay, harbouring a DTU associated with severe Chagas disease in humans.

Resumo Com o objetivo de verificar a infecção natural por Trypanosoma cruzi em primatas não-humanos de uma área endêmica rural da região leste do Paraguai, foi realizado o xenodiagnóstico em 35 animais pertencentes a duas espécies. Para a genotipagem foi utilizada a unidade discreta de tipagem (UDT) do T. cruzi, em uma combinação de quatro marcadores, incluindo amplificação de produtos de pequena (18S) e grande (24Sα) subunidades do gene do ácido ribonucleico ribossômico, da região intergênica de miniéxon e do gene da proteína de choque térmico 60 (HSP60/EcoRV-PCR-RFLP), pela reação em cadeia da Polimerase. Um espécime de Sapajus cay se mostrou positivo pelo UDT TcII. Este resultado constitui o primeiro relato da infecção natural pelo T. cruzi em um macaco silvestre no Paraguai, abrigando um UDT associado com a doença de Chagas grave em humanos.

Characteristics of Triatomine infestation and natural Trypanosoma cruzi infection in the State of Rio Grande do Norte, Brazil

Abstract: INTRODUCTION Natural and artificial ecotope infestation by the kissing bug triatomines and their colonization and infection by Trypanosoma cruzi , the Chagas disease agent, were evaluated in nine municipalities of the State of Rio Grande do Norte, Brazil. METHODS Following identification, triatomine intestinal contents were analyzed by direct microscopic examination, xenoculture, and polymerase chain reaction (PCR) for parasite detection. Trypanosoma cruzi isolates were genotyped using three different markers. RESULTS Of 842 triatomines captured, 65% were Triatoma brasiliensis , 17.8% Triatoma pseudomaculata , 12.5% Panstrongylus lutzi , and 4.7% Rhodnius nasutus . Triatoma brasiliensis and P. lutzi adults were found in the intradomicile. T. brasiliensis, T. pseudomaculata , and R. nasutus nymphs and adults were found in the peridomicile and wild environment. Intradomiciliary and peridomiciliary infestation indexes were 5.6% and 33.7%, respectively. In the peridomicile, chicken coops were the most infested ecotope. The T. cruzi triatomine infection rate was 30.2%, of which PCR detected 29%. P . lutzi (78.1%), T . brasiliensis (24.5%), and T . pseudomaculata (22.7%) were the most infected species. TcII and III genotypes were detected in T. brasiliensis and TcIII in P. lutzi . CONCLUSIONS T. brasiliensis was found in all environments and most ecotopes with high T. cruzi infection rates. High infection rates were also detected in T . pseudomaculata and P. lutzi , suggesting their role in the interchange between the wild and peridomestic transmission cycles. The combination of PCR, microscopic examination, and xenoculture contributed to improving T. cruzi infection evaluation in triatomine bugs. The TcII and TcIII genotypes were predominant in the study area.

Trypanosoma cruzi -infected Triatoma gerstaeckeri (Hemiptera: Reduviidae) from Nuevo León, México, and pathogenicity of the regional strain / Triatoma gerstaeckeri (Hemiptera: Reduviidae) infectada con Trypanosoma cruzi en Nuevo León, México, y capacidad patógena de la cepa regional

Introduction: Four species of triatomines have been reported in Nuevo León, northeast (NE) México, but Triatoma gerstaeckeri has only been recorded from a peridomestic dwelling. Objectives: To assess the natural infection index (NII) of Trypanosoma cruzi in triatomines and the infestation index (II) of T. gerstaeckeri collected in a suburban locality, and to collect histopathological data to understand tissue tropism of the regional T. cruzi strain (strain NE) obtained from the vectors collected after an experimental inoculation in Mus musculus . Materials and methods: Triatomines were collected from 85 houses and peridomiciles in Allende, Nuevo León. Stool samples were obtained to determine the T. cruzi NII and were used in an experimental mice infection. Results: A total of 118 T . gerstaeckeri were captured, and 46 (adults and nymphs) were collected inside the same house (II=1.17%). Thirty-seven reduvids were infected with T. cruzi (NII=31.3%). Tissue tropism of the T. cruzi NE strain was progressive in skeletal muscle, myocardial, and adipose tissues and was characterized by the presence of intracellular amastigotes and destruction of cardiac myocells. Conclusions: The presence of naturally infected domiciliary vectors is an important risk factor for public health in the region considering that these vectors are the principal transmission mechanism of the parasite. The T. cruzi NE strain has similar virulence to that of other Mexican and Texan strains and caused chagasic infections in 11 of 12 mice.

Introducción. En Nuevo León, localizado en el noreste de México, existen cuatro especies de triatominos, de las cuales Triatoma gerstaeckeri ha sido la única reportada en peridomicilios. Objetivos. Evaluar el índice de infección natural de Trypanosoma cruzi en los triatominos y el índice de infestación de T. gerstaeckeri en una localidad suburbana, y obtener datos histopatológicos para comprender el tropismo tisular de la cepa regional (cepa NE) de T. cruzi obtenida de los vectores recolectados después de la infección experimental en Mus musculus. Materiales y métodos. La recolección de triatominos se llevó a cabo en 85 casas y peridomicilios de Allende, Nuevo León, México. Se obtuvieron muestras de las deyecciones para conocer el índice de infección natural por T. cruzi y, con estas, se hicieron inoculaciones experimentales en ratones. Resultados. Se capturaron 118 especímenes de T. gerstaeckeri , 46 (adultos y ninfas) en el mismo domicilio (índice de infestación=1,17 %). Treinta y siete redúvidos estaban infectados con T. cruzi (índice de infección natural, 31,3). El tropismo tisular de la cepa NE de T. cruzi fue progresivo en músculo esquelético, miocardio y tejido adiposo, y se caracterizó por la presencia de amastigotes intracelulares con destrucción de células cardiacas. Conclusiones. La presencia de vectores domiciliarios naturalmente infectados con T. cruzi , es un factor de riesgo importante para la salud pública de la región, considerando que este es el principal mecanismo de la transmisión del parásito y que la cepa NE de T. cruzi tiene una virulencia similar a la de otras cepas mexicanas y texanas, y causó infección chagásica en 11 de los 12 ratones inoculados.

First report of acute Chagas disease by vector transmission in Rio de Janeiro State, Brazil / Primeiro relato de doença de Chagas aguda por transmissão vetorial no Estado do Rio de Janeiro, Brasil

SUMMARYChagas disease (CD) is an endemic anthropozoonosis from Latin America of which the main means of transmission is the contact of skin lesions or mucosa with the feces of triatomine bugs infected by Trypanosoma cruzi. In this article, we describe the first acute CD case acquired by vector transmission in the Rio de Janeiro State and confirmed by parasitological, serological and PCR tests. The patient presented acute cardiomyopathy and pericardial effusion without cardiac tamponade. Together with fever and malaise, a 3 cm wide erythematous, non-pruritic, papule compatible with a "chagoma" was found on his left wrist. This case report draws attention to the possible transmission of CD by non-domiciled native vectors in non-endemic areas. Therefore, acute CD should be included in the diagnostic workout of febrile diseases and acute myopericarditis in Rio de Janeiro.

RESUMOA doença de Chagas é antropozoonose endêmica na América Latina que tem como principal mecanismo de transmissão humana o contato da pele lesada ou da mucosa com as fezes de triatomíneos infectados por Trypanosoma cruzi. Neste artigo descrevemos o primeiro caso de doença de Chagas aguda adquirida no Estado do Rio de Janeiro por transmissão vetorial com confirmação parasitológica, sorológica e pela PCR. O paciente apresentou miocardite aguda e derrame pericárdico de evolução benigna. Juntamente com as manifestações sistêmicas da fase aguda, foi notada pápula eritematosa de três cm de diâmetro compatível com chagoma em punho esquerdo. Este relato de caso chama a atenção para a possibilidade de transmissão da doença de Chagas por vetores nativos não domiciliados e em áreas consideradas indenes. Portanto, a doença de Chagas aguda deve ser incluída entre os diagnósticos diferenciais de doenças febris e miopericardites agudas no Rio de Janeiro.

Domestic, peridomestic and wild hosts in the transmission of Trypanosoma cruzi in the Caatinga area colonised by Triatoma brasiliensis

The role played by different mammal species in the maintenance of Trypanosoma cruzi is not constant and varies in time and place. This study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of T. cruzi in Tauá, state of Ceará, Caatinga area, Brazil, with an emphasis on those environments colonised by Triatoma brasiliensis. Direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and outdoor mammals and multiplex polymerase chain reaction was used on wild mammals. Cytochrome b was used as a food source for wild insects. The serum prevalence in dogs was 38% (20/53), while in pigs it was 6% (2/34). The percentages of the most abundantly infected wild animals were as follows: Thrichomys laurentius 74% (83/112) and Kerodon rupestris 10% (11/112). Of the 749 triatomines collected in the household research, 49.3% (369/749) were positive for T. brasiliensis, while 6.8% were infected with T. cruzi (25/369). In captured animals, T. brasiliensis shares a natural environment with T. laurentius, K. rupestris, Didelphis albiventris, Monodelphis domestica, Galea spixii, Wiedomys pyrrhorhinos, Conepatus semistriatus and Mus musculus. In animals identified via their food source, T. brasiliensis shares a natural environment with G. spixii, K. rupestris, Capra hircus, Gallus gallus, Tropidurus oreadicus and Tupinambis merianae. The high prevalence of T. cruzi in household and peridomiciliar animals reinforces the narrow relationship between the enzootic cycle and humans in environments with T. brasiliensis and characterises it as ubiquitous.

The peri-urban interface and house infestation with Triatoma infestans in the Argentine Chaco: an underreported process?

Peri-urban infestations with triatomine bugs, their sources and their dynamics have rarely been investigated. Here, we corroborated the reported occurrence of Triatoma infestans in a peri-urban area and in neighbouring rural houses in Pampa del Indio, in the Argentine Chaco, and identified its putative sources using spatial analysis and demographic questionnaires. Peri-urban householders reported that 10% of their premises had triatomines, whereas T. infestans was collected by timed manual searches or community-based surveillance in only nine (3%) houses. Trypanosoma cruzi-infected T. infestans and Triatoma sordida were collected indoors only in peri-urban houses and were infected with TcV and TcI, respectively. The triatomines fed on chickens, cats and humans. Peri-urban infestations were most frequent in a squatter settlement and particularly within the recently built mud houses of rural immigrants, with large-sized households, more dogs and cats and more crowding. Several of the observed infestations were most likely associated with passive bug transport from other sources and with active bug dispersal from neighbouring foci. Thus, the households in the squatter settlement were at a greater risk of bug invasion and colonisation. In sum, the incipient process of domestic colonisation and transmission, along with persistent rural-to-urban migratory flows and unplanned urbanisation, indicate the need for active vector surveillance and control actions at the peri-urban interface of the Gran Chaco.

Evaluation of the Chagas Disease Control Program in Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil

Introduction Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil temporarily (2001-2005) interrupted epidemiological surveillance for Chagas disease. The objective of this work was to evaluate the Chagas Disease Control Program (CDCP) in Açucena and to offer suggestions for improving local epidemiological surveillance. Methods This study was conducted in three phases: I) a serological investigation of schoolchildren aged 5 to 15 years using an enzyme-linked immunosorbent assay (ELISA) test performed on blood collected on filter paper followed by ELISA, indirect immunofluorescence (IIF) and indirect hemaglutination (IHA) on venous blood for borderline cases and those in the gray zone of reactivity; II) vector evaluation using the data obtained by local health agents during 2006-2010; and III) examination by ELISA, IIF and IHA of serum samples from the inhabitants of houses where infected Triatoma vitticeps was found and evaluation of their knowledge about Chagas disease. Results Five individuals had inconclusive results in the ELISA screening but were seronegative for Chagas disease. The triatomine evaluation revealed the presence of three species: Triatoma vitticeps, Panstrongylus megistus and Panstrongylus diasi. Triatoma vitticeps was the most prevalent and widespread, with a higher (67%) index of Trypanosoma cruzi flagellates and evidence of colonization. Most of the inhabitants of the infested houses recognized triatomines and had basic knowledge about Chagas disease. Conclusions Although T. vitticeps is not clearly associated with Chagas disease transmission, these results highlight the importance of maintaining CDCP in endemic areas and the need for greater emphasis on epidemiological surveillance, especially in areas with important vectorial changes or that have been modified by human intervention. .

An entomoepidemiological investigation of Chagas disease in the state of Ceará, Northeast Region of Brazil / Investigação entomoepidemiológica da doença de Chagas no Estado do Ceará, Nordeste do Brasil / Investigación entomoepidemiológica de la enfermedad de Chagas en el estado de Ceará, noreste de Brasil

The seroprevalence of Chagas disease in humans and the presence of triatomines were investigated in a rural locality in the State of Ceará, Brazil, an historically endemic region. Approximately 80% of the surveyed residents agreed to undergo serological tests. Intradomestic and peridomestic environments were searched for triatomines in both the dry and rainy seasons. The prevalence rate of Chagas disease was 1.2% and the majority of individuals confirmed with the disease over 50 years of age. A total of 761 specimens of triatomines were captured, most of which were from colonies composed of nymphs and adult bugs, and the majority of specimens were obtained in the dry season. Triatoma brasiliensis was the predominant species. Analysis using light microscopy revealed that 28.6% of the insects were Trypanosoma cruzi positive. Results suggest that peridomestic man-made structures, such as animal shelters, improper storage of timber and uninhabited dwellings contribute to the high rate of triatomine infestation in the area.

A presença de triatomíneos e a soroprevalência da infecção chagásica humana foram investigadas em uma localidade rural do Estado do Ceará, Brasil, região endêmica histórica da doença de Chagas. Os triatomíneos foram pesquisados nos domicílios, nos períodos de seca e de chuva. A soroprevalência encontrada no período foi de 1,2%, maior entre pessoas com mais de 50 anos de idade, e sem diferença significativa em relação ao sexo. Foram capturados 761 espécimes de triatomíneos, em colônias compostas de ninfas e insetos adultos, com predominância de Triatoma brasiliensis, especialmente no período de seca. O exame do conteúdo intestinal dos insetos revelou que 28,6% eram Trypanosoma cruzi positivos. Os resultados sugerem que os abrigos de animais e armazenamento inadequado de materiais no peridomicílio, particularmente amontoados de madeiras, bem como moradias desabitadas, contribuem para o alto índice de infestação de triatomíneos na localidade.

Se investigó la presencia de insectos y seroprevalencia en la infección humana por Trypanosoma cruzi, en un área rural del estado de Ceará, Brasil, región endémica histórica de la enfermedad Chagas. Se informó sobre la presencia de insectos en los hogares durante los períodos de sequía y lluvia. La seroprevalencia en el período fue un 1,2%, mayor entre las personas de más de 50 años de edad, y no hubo diferencias significativas en relación al sexo. Se capturaron 761 ejemplares de insectos en colonias compuestas por ninfas y adultos de insectos, principalmente, Triatoma brasiliensis, especialmente durante la estación seca. El examen del contenido intestinal de los insectos reveló que un 28,6% eran T. cruzi positivo. Los resultados sugieren que los refugios de animales y el almacenamiento inadecuado de materiales fuera del hogar, especialmente pilas de madera y casas deshabitadas, contribuyen a la alta tasa de infestación de insectos en la localidad.

Behavioural biology of Chagas disease vectors

Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology.

Chronic Chagas disease: PCR-xenodiagnosis without previous microscopic observation is a useful tool to detect viable Trypanosoma cruzi

We evaluate the elimination of the microscopic stage of conventional xenodiagnosis (XD) to optimize the parasitological diagnosis of Trypanosoma cruzi in chronic Chagas disease. To this purpose we applied under informed consent two XD cages to 150 Chilean chronic chagasic patients. The fecal samples (FS) of the triatomines at 30, 60 and 90 days post feeding were divided into two parts: in one a microscopic search for mobile trypomastigote and/or epimastigote forms was performed. In the other part, DNA extraction-purification for PCR directed to the conserved region of kDNA minicircles of trypanosomes (PCR-XD), without previous microscopic observation was done. An XD was considered positive when at least one mobile T. cruzi parasite in any one of three periods of incubation was observed, whereas PCR-XD was considered positive when the 330 bp band specific for T. cruzi was detected. 25 of 26 cases with positive conventional XD were PCR-XD positive (concordance 96.2%), whereas 85 of 124 cases with negative conventional XD were positive by PCR-XD (68.5%). Human chromosome 12 detected by Real-time PCR used as exogenous internal control of PCR-XD reaction allowed to discounting of PCR inhibition and false negative in 40 cases with negative PCR-XD. Conclusion: PCR-XD performed without previous microscopic observation is a useful tool for detection of viable parasites with higher efficiency then conventional XD.